set @page = 10069356;

select page_title from page join

(select a, locate('(', a) as 'c', if(locate('(', a) > 0, substring(a,1,locate('(', a)-2), a) as d from

(select pl_title as 'a' from pagelinks

where pl_from = @page

and not pl_namespace

union

select page_title as 'a' from page

where page_id in

(select tl_from from templatelinks

 where tl_target_id = 21855)

 and not page_namespace) t0

 order by a)

where (page_title = d

       or page_title like concat(d, '_(%)'))

and not page_namespace;

​